I'm not an artist (this is more tracing over a reference photo than drawing), just an indigent book author who wants to use some pictures of famous people without paying royalties. I wanted to see if I could achieve a pencil drawing look in InkScape. The result is more or less good enough for my purposes, lots of lines and lots of Gaussian blurs.

I think I learned that using vectors doesn't really let me postpone knowing what the final size is. Rescaling fine lines and subtle shading without disturbing balance is probably a pipedream. I think I either need to do these at final scale or perhaps 2x while staying aware that dimensions (e.g. line widths) will be halved. As always, knowing how final web press printing on paper at 600dpi will differ in look is a problem.

Wow, that must have taken hours! Would be interesting to be able to look into the SVG file, to see how you created certain effects. Although it's understandable you might not want to share it, if it going to be published later.

Did you use a graphics tablet or just mouse?

I can't help with the printing and dpi issues. It's so confusing! But of course you realize that you can scale the vector drawing, literally at will, without losing any quality. It's just figuring out what size to export, in the end. And as long as you save the original SVG, you can keep on tweaking and trial and error, until you get it right.

I used my cheap Huion tablet, but probably less than 10% of the time. The tablet was faster for hair and long lines (like outline of head). Complex shapes for shading were almost always faster with the Bezier line draw, because there's going to be so much blur having a precision shape doesn't matter.

The glasses are just typical geometric shapes that most people could do much better/quicker than me . The visible "pencil lines" are just drawn with the pencil tool, then adjust the tone and blur.

The head hair was using the pencil tool with tablet, just drawing hair lines fast and imprecise. For laziness, I might select a group of hairs, copy and paste to new location, shift/shrink/rotate as needed. After all the head hair was drawn (not really that many), I selected all and simplified (Ctrl-L). To vary the hair color, I would Shift-select several hairs here and there and give them a different tone to get a "streaking" effect. The last step was selecting all the hair and playing with the Blur until the effect was pleasing.

Once it dawned on me that the only way to get white whiskers was to back them with some darker tone, they were just fast drawing with the pencil tool ("triangle in", I think for little points the end that probably no one will notice anyway). Same copy/paste/shift/resize/rotate as with the head hair to be lazy about it.

The shading is what I wasted the most time on because I wasn't thinking simply enough. The final technique was: a) identify an irregular shape with roughly the same tonal value, b) draw filled shape quickly with Bezier straight line tool, c) play with Blur and Lightness until it matches the desired tone well enough.

I spent a lot of hours trying more complex techniques that didn't seem to produce as good an effect, so hopefully my next "head shot" will go a whole lot quicker.